speakers make the sound we hear in our rooms... and wonderful sound is what we are striving for in our rooms
speakers should be evaluated when performing at their best, which is properly set up in room, driven by a suitable amp to get peak performance (or something very close to it) from them
efficiency of the speaker, and the requisite amp, are all part of the tradeoffs to get the sound we really want
all others things equal, yes, easy to drive, efficient speakers are nice to have... but it is foremost about the sound... that is the big dog that wags the tail of efficiency and amplification